Driver-information systems, which are each installed in the vehicle as additional devices, together with their own output unit, are already known in vehicles. Examples include navigation devices, car-radio devices, or on-board computers for displaying vehicle parameters such as fuel consumption. The car radio has, for example, a display for the tuned-in station. In addition, display elements for the display of quantities relating to operation and safety are known in vehicles. An example is a combination instrument, which, among the various displays, may indicate the vehicle speed or, as an example of vehicle malfunction, may indicate a brake failure. The combination instrument includes a plurality of displays of quantities relevant to the vehicle, such as the vehicle speed, the engine speed, or the fill level of the tank. While the functions represented in the displays are identical in many vehicles, different manufacturers or different users require the appearance of output units, operating units, or displays to be different. Therefore, it is necessary to produce an appropriate output unit for each different vehicle type, and to connect it to the respective device. In addition, each different device requires its own display.